Various efforts have been made to provide engraved ceramic articles, such as tile, concrete articles, plaster articles, refractory articles, and brick. Such articles are somewhat difficult to engrave in a manner which produces an aesthetically pleasing product. The compositions of such ceramic articles do not lend themselves to precise engraving methods. Efforts have been made to provide engraved brick for promotional, commemorative and other purposes utilizing laser beams and expensive, specialized laser beam generating equipment. Prior art efforts have produced results which are not always aesthetically suitable or economical.
Accordingly, there has been a continuing need to provide improved engraved ceramic articles, such as brick, which may be carried out with relatively inexpensive capital equipment so as to be cost effective while producing an aesthetically pleasing product. It is to these ends that the present invention has been developed.
The present invention provides an improved method of engraving ceramic articles, such as brick, articles of concrete and limestone and ceramic tile, whereby a precisely guided laser beam is used to carry out the engraving process. Commercially available equipment is used to generate a laser beam of modest power output and the characteristics of the beam, together with a method of steering the beam to engrave lettering and other graphic representations, produces a more aesthetically pleasing article in an efficient and economical manner.
In accordance with one aspect of the present invention, a method is provided for precision engraving conventional construction and paving brick, for example, wherein certain graphics, such as lettering which may include a name or word, may be engraved on the face of the brick. Other graphic representations may also be engraved using the laser engraving process of the present invention.
In accordance with another aspect of the present invention, an engraving process for brick and other ceramic articles is provided using commercially available laser equipment having a focusing lens which reduces the laser beam diameter to a predetermined dimension upon delivery of the beam from the laser itself. A suitable beam intensity is derived from such an arrangement of beam treatment which has been discovered to be particularly advantageous for engraving brick and the like when used in conjunction with other parameters of the process of the invention.
In accordance with a further aspect of the present invention, a brick engraving process is provided wherein a laser beam is guided in such a way as to complete the engraving of a graphic character or characters, such as one or more English letters which are engraved into the brick, and wherein each letter is engraved in at least one pass over the character before the laser beam is steered to begin engraving the next letter or graphic character. In this way, heat generated by the laser does not dissipate away from the specific area of the brick or other ceramic article on which the engraving process is being carried out, thus resulting in a more effective engraving process.
The present invention also provides an engraving process wherein a suitable depth of engraving may be accomplished on articles, such as conventional brick, by making one and, preferably, no more than two passes of the laser beam over the article being engraved. For the particular power output of the laser and the beam width imposed on the article, a desired depth of engraving and surface characteristics of engraving are provided which yield a desirable finish or visual impression of the engraving.
Those skilled in the art will further appreciate the above-mentioned advantages and superior features of the invention upon reading the detailed description which follows in conjunction with the drawings.